Comparing the Performance of Three Models Incorporating Weather Data to Forecast Dengue Epidemics in Reunion Island, 2018-2019.

We developed mathematical models to analyze a large dengue virus (DENV) epidemic in Reunion Island in 2018-2019. Our models captured major drivers of uncertainty including the complex relationship between climate and DENV transmission, temperature trends, and underreporting. Early assessment correctly concluded that persistence of DENV transmission during the austral winter 2018 was likely and that the second epidemic wave would be larger than the first one. From November 2018, the detection probability was estimated at 10%-20% and, for this range of values, our projections were found to be remarkably accurate. Overall, we estimated that 8% and 18% of the population were infected during the first and second wave, respectively. Out of the 3 models considered, the best-fitting one was calibrated to laboratory entomological data, and accounted for temperature but not precipitation. This study showcases the contribution of modeling to strengthen risk assessments and planning of national and local authorities.

Impact of the COVID-19 pandemic and lockdowns on emergency data related to mental health disorders in Nouvelle-Aquitaine, France.

This study estimates the association between emergency department (ED) visits for mental health disorders (MHDs) and the health context of the COVID-19 pandemic in the French region of Nouvelle-Aquitaine. This retrospective study took place between 2018 and 2021 using ED data. We defined the main exposure according to five periods: "Pre-pandemic (reference)", "First lockdown", "Second lockdown", "Third lockdown", and "Pandemic out-of-lockdown." We constructed the daily indicators for each MHD-related ED visit based on medical diagnoses. We described and then modeled the daily time series using generalized additive models with a quasi-Poisson regression. The analysis included 5,693,341 ED visits of which MHDs accounted for 4%. We observed a decline in ED use for most indicators, particularly during the first lockdown. Models revealed a statistically significant relative increase in ED visits for almost all MHDs during the first lockdown; for anxiety and child psychiatric disorders during the second lockdown; and only for child psychiatric disorders during the pandemic out-of-lockdown period. The public health crisis and lockdowns associated with the COVID-19 pandemic have been important sources of stress that could partially explain the deterioration of MHD indicators, thus leading to new public health concerns (notably among the youngest age group). Mental health is a major determinant of overall health and should therefore be considered in the management of crises that may require similar responses in the future.

COVID-19 hotspots through clusters analysis in France (may-October 2020): where should we track the virus to mitigate the spread?

BACKGROUND: In France, the lifting of the lockdown implemented to control the COVID-19 first wave in 2020 was followed by a reinforced contact-tracing (CT) strategy for the early detection of cases and transmission chains. We developed a reporting system of clusters defined as at least three COVID-19 cases, within seven days and belonging to the same community or having participated in the same gathering, whether they know each other or not. The aim of this study was to describe the typology and criticality of clusters reported between the two lockdowns in France to guide future action prioritisation. METHODS: In this study we describe the typology and criticality of COVID-19 clusters between the two lockdowns implemented in France (between May and end of October 2020). Clusters were registered in a national database named "MONIC" (MONItoring des Clusters), established in May 2020. This surveillance system identified the most affected communities in a timely manner. A level of criticality was defined for each cluster to take into consideration the risk of spreading within and outside the community of occurrence, and the health impact within the community. We compared the level of criticality according to the type of community in which the cluster occurred using Pearson's chi-square tests. RESULTS: A total of 7236 clusters were reported over the study period, particularly in occupational environment (25.1%, n = 1813), elderly care structures (21.9%, n = 1586), and educational establishments (15.9%, n = 1154). We show a shift over time of the most affected communities in terms of number of clusters. Clusters reported in occupational environment and the personal sphere had increased during summer while clusters reported in educational environment increased after the start of the school year. This trend mirrors change of transmission pattern overtime according to social contacts. Among all reported clusters, 43.1% had a high level of criticality with significant differences between communities (p < 0.0001). A majority of clusters had a high level of criticality in elderly care structures (82.2%), in disability care centres (56.6%), and health care facilities (51.7%). CONCLUSION: These results highlight the importance of targeting public health action based on timely sustained investigations, testing capacity and targeted awareness campaigns. The emergence of new SARS-CoV-2 variants strengthen these public health recommendations and the need for rapid and prioritise vaccination campaigns.

Impact des deux confinements sur le recours aux soins d'urgence lors de l'épidémie de COVID-19 en Nouvelle-Aquitaine.

INTRODUCTION: Following the emergence of the COVID-19 epidemic in France, several preventive measures have been put in place, including a mandatory lockdown of the entire population. This measure was intended to slow down the viral circulation and protect the healthcare system, especially hospital departments. The aim of this study was to describe the activity of emergency department (ED) during the two lockdowns related to the COVID-19 epidemic in the Nouvelle-Aquitaine region. METHOD: A retrospective descriptive analysis of ED visits was performed for the period December 09, 2019 to December 20, 2020. The distribution of the number of ED visits was studied. RESULTS: ED visits decreased by 50% during the first lockdown in line with the COVID-19 epidemic and by 30% during the second. Hospitalization rate increased during the two lockdowns (+ 48% and + 20%, respectively). A differentiated use was observed during both lockdowns, with the emergence of the use of care for "coronavirus", "stroke" or "dyspnea / respiratory failure" while the typical pathologies "ENT infections" or "skin infections" were no more or less observed. CONCLUSION: Data from Oscour® allowed a real-time monitoring of the COVID-19 epidemic in France, and to assess the impact of lockdown on ED activity in the region. A decline in the use of healthcare services, the increase in hospitalization rate and the pathologies observed during the two lockdowns are in favour of a refocusing of the recourse for most serious pathologies.

From the threat to the large outbreak: dengue on Reunion Island, 2015 to 2018.

BackgroundWith more than 300 million infections estimated annually worldwide, dengue is the most prevalent arboviral infection. On Reunion Island, after a large outbreak in 1977-78, only limited episodes of viral circulation or sporadic cases were reported till 2015.AimOur objective was to document and report on the circulation of dengue virus after the occurrence of a small outbreak during austral summer 2015/16 and until the large outbreak of 2018.MethodsBeside the mandatory notification of biologically confirmed dengue cases, additional systems of surveillance were set up: estimation of dengue-like syndrome in people seeking care by their family doctor, surveillance of emergency department visits related to dengue, surveillance of hospitalised dengue patients and deaths classifications.ResultsAfter a moderate outbreak during summer 2015/16 with 231 cases, 2017 was characterised by limited viral circulation (97 cases) which, however, persisted during the austral winter. By February 2018, the number of cases had increased and led to a peak at the beginning of May 2018. More than 6,000 cases were reported this year (dengue virus type 2 only). In addition, six deaths of dengue patients were notified.ConclusionIn 2017, the persistence of transmission during winter created favourable conditions for the emergence of an epidemic during summer 2018. After this moderate epidemic wave, the viral circulation persisted during winter 2018 for the second year, opening the door for the second wave in 2019 and for potential endemisation of the disease on Reunion Island in the near future.

Costs of Conjunctivitis Outbreak, Réunion Island, France.

During January-April 2015, a major outbreak of conjunctivitis on Réunion Island caused a large public health impact. On the basis of general practitioner consultations, emergency department visits, and eye medication sales during the 13-week epidemic, we estimated a total healthcare cost of €3,341,191 from the outbreak.

Emergency department syndromic surveillance to investigate the health impact and factors associated with alcohol intoxication in Reunion Island.

In Reunion Island, alcohol is the most tried out psychoactive substance. To our knowledge, few indicators measuring the health burden of alcohol use exist on the island. In this context, an exploratory analysis based on syndromic surveillance data was implemented in order to describe the emergency department (ED) visits for alcohol intoxication (AI) and factors associated with their variations.An analysis of anonymized records routinely collected by the syndromic surveillance system was carried out. A daily indicator of ED visits for AI was built from a selection of ICD-10 codes between 2010 and 2012. Health impact of AI was first described comparing this indicator to all causes ED visits. Then, AI visits were analyzed with time-series methods using generalized additive Poisson regression models allowing for overdispersion. The following variables were included in the model: long-term trend, seasonality, day of the week, public and school holidays, days of festival and minimum social benefits payday.During the study period, 16 652 visits for AI were recorded in EDs of Reunion Island. AI visits were the second reason for ED visits (i.e. 4%) after traumatism. AI visits mainly concerned men (87%) and the age group of 25-54 years (69%). There was a significant increase in ED visits for AI during days of benefits payday, weekends and publics holidays.This study demonstrated the interest of syndromic surveillance to monitor non-infectious diseases. Time-series models showed a robust association between ED visits for AI and several factors.

A major outbreak of conjunctivitis caused by coxsackievirus A24, Réunion, January to April 2015.

From January to April 2015, Réunion experienced a major outbreak of acute haemorrhagic conjunctivitis (AHC) caused by coxsackievirus A24, which heavily impacted the healthcare system. According to the general practitioners' (GP) sentinel network, the number of medical consultations due to conjunctivitis during this period was estimated at ca 100,000. This report describes the characteristics of the outbreak, which were obtained through several different yet complementary surveillance systems on the island. These included the network of hospital emergency departments (OSCOUR network), the GPs' sentinel network, an Internet-based population cohort ('Koman i lé') participating in a survey on distinct symptoms including 'red eyes' and the monitoring of eye drop sales. Overall the results of the different surveillance approaches were in good agreement regarding the outbreak dynamic. A peak of patients with conjunctivitis was detected in the first 15 days of March (week 10 and 11), coinciding with increased eye drop sales on the island. Strains recovered from outbreak cases belonged to genotype IV and were most closely related to strains identified in AHC outbreaks in China, Egypt and Japan since 2010. Continued surveillance of AHC in Réunion remains important not only locally, but also because frequent exchanges between the island and mainland France may lead to introduction of this virus in Europe.

Réunion Island prepared for possible Zika virus emergence, 2016.

Zika virus (ZIKV) has recently spread widely and turned into a major international public health threat. Réunion appears to offer conditions particularly favourable to its emergence and therefore prepared to face possible introduction of the virus. We designed a scaled surveillance and response system with specific objectives, methods and measures for various epidemiological phases including a potential epidemic. Several tools were developed in order to (i) detect individual cases (including a large information campaign on the disease and suspicion criteria), (ii) monitor an outbreak through several complementary systems allowing to monitor trends in disease occurrence and geographic spread and (iii) detect severe forms of the disease in collaboration with hospital clinicians. We put the emphasis on detecting the first cases in order to contain the spread of the virus as much as possible and try to avoid progress towards an epidemic. Our two main strengths are a powerful vector control team, and a close collaboration between clinicians, virologists, epidemiologists, entomologists and public health authorities. Our planned surveillance system could be relevant to Europe and island settings threatened by Zika virus all over the world.

Health impact assessment of cyclone Bejisa in Reunion Island (France) using syndromic surveillance.

INTRODUCTION: On January 2, 2014, Cyclone Bejisa struck Reunion Island (France). This storm led to major material damages, such as power outages, disturbance of drinking water systems, road closures, and the evacuation of residents. In this context, the Regional Office of French Institute for Public Health Surveillance in Indian Ocean (Cire OI) set up an epidemiological surveillance in order to describe short-term health effects of the cyclone. METHODS: The assessment of the health impact was based mainly on a syndromic surveillance system, including the activity of all emergency departments (EDs) and the Emergency Medical Service (EMS) of the island. From these data, several health indicators were collected and analyzed daily and weekly. To complete this assessment, all medical charts recorded in the EDs of Reunion Island from January 2, 2014 through January 5, 2014 were reviewed in order to identify visits directly and indirectly related to the cyclone, and to determine mechanisms of injuries. RESULTS: The number of calls to the EMS peaked the day of the cyclone, and the number of ED visits increased markedly over the next two days. At the same time, a significant increase in visits for trauma, burns, and carbon monoxide poisoning was detected in all EDs. Among 1,748 medical records reviewed, eight visits were directly related to the cyclone and 208 were indirectly related. For trauma, the main mechanisms of injury were falls and injuries by machinery or tools during the clean-up and repair works. Due to prolonged power outages, several patients were hospitalized: some to assure continuity of care, others to take care of an exacerbation of a chronic disease. An increase in leptospirosis cases linked to post-cyclone clean-up was observed two weeks after the cyclone. CONCLUSION: Information based on the syndromic surveillance system allowed the authors to assess rapidly the health impact of Cyclone Bejisa in Reunion Island; however, an underestimation of this impact was still possible. In the near future, several lines of work will be planned by the authors in order to improve the assessment.

Bronchiolitis 2022-2023: One of the most unexpected outbreaks over this past decade, Nouvelle-Aquitaine, France.

BACKGROUND: Since the Covid-19 pandemic, bronchiolitis outbreaks have been subject to disrupted seasonality, and a major impact on the healthcare system was observed in 2022-23. OBJECTIVE: The aim of this article is to describe the characteristics of the 2022-23 bronchiolitis epidemic in the Nouvelle-Aquitaine region, and its impact on the healthcare system. METHOD: We described the indicators of dynamics, intensity, severity and impact provided by the bronchiolitis monitoring in place, and compared these with those from previous seasons. RESULTS: The intensity of the 2022-23 epidemic (emergency department visits: 23 %; SOS Médecins acts: 15 %), and its impact in terms of bronchiolitis-related hospitalizations (45 %) were higher than in previous seasons (p < 0.05). CONCLUSION: In addition to earliness, the 2022-23 bronchiolitis epidemic was significant as regards its exceptional scale and major impact on the hospital system, requiring adaptation of the preexisting healthcare offer in response to the anticipated demand.

Leprosy on Reunion Island, 2005-2013: Situation and Perspectives.

BACKGROUND: Reunion Island is a French overseas territory located in the south-western of Indian Ocean, 700 km east of Madagascar. Leprosy first arrived on Reunion Island in the early 1700s with the African slaves and immigration from Madagascar. The disease was endemic until 1980 but improvement of health care and life conditions of inhabitants in the island have allowed a strong decrease in new cases of leprosy. However, the reintroduction of the disease by migrants from endemic neighbouring countries like Comoros and Madagascar is a real and continuing risk. This observational study was then conducted to measure the number of new cases detected annually on Reunion Island between 2005 and 2013, and to describe the clinical features of these patients. METHODOLOGY/PRINCIPAL FINDINGS: Data were collected over two distinct periods. Incident cases between 2005 and 2010 come from a retrospective study conducted in 2010 by the regional Office of French Institute for Public Health Surveillance (CIRE of Indian Ocean), when no surveillance system exist. Cases between 2011 and 2013 come from a prospective collection of all new cases, following the implementation of systematic notification of all new cases. All patient data were anonymized. Among the 25 new cases, 12 are Reunion Island residents who never lived outside Reunion Island, and hence are considered to be confirmed autochthonous patients. Registered prevalence in 2014 was 0.05 /10 000 habitants, less than the WHO's eradication goal (1/10 000). CONCLUSIONS/SIGNIFICANCE: Leprosy is no longer a major public health problem on Reunion Island, as its low prevalence rate indicates. However, the risk of recrudescence of the disease and of renewed autochthonous transmission remains real. In this context, active case detection must be pursued through the active declaration and rapid treatment of all new cases.